Integer Tic-Tac-Toe (Teaching multiplication of negatives and positives)

I created a tic-tac-toe game to help kids distinguish between multiplying negatives and positives. Use the same board but use + and - instead of x and o.  Next have each player pic a square that is theirs. Have them place a + or - symbol beside the square and what ever goes inside must first be multiplied by the - or the +.

Example,

if you place a - inside a "+ charged square" the square becomes negative

if you place a - inside a "- charged square" the square becomes positive